SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'de090fd6d44faabdb52216473fee728ad825e696f6d4f25ec7afc725a22214ac' 
  AND token = 'wVnrV93UkjRtIfIEsOmPQW45Oj8+MuqlljWrMhUUg3U=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}